1. Field of the Invention
The present invention relates to a rear body structure for a vehicle and, more particularly, to a rear body structure for a rear body structure having a high-mount backbone frame.
2. Description of Related Art
There has been known vehicle bodies having what is called a high-mount backbone frame such as disclosed in, for example, Japanese Unexamined Patent Publication No. 2000-23 8667. The high-mount backbone frame, that is known as a floor tunnel reinforcement a floor tunnel reinforcement disposed on a floor extending in a lengthwise direction of a vehicle body at a central portion of a floor panel and forming a closed cross section between them. This type of floor tunnel reinforcement provides improvement of rigidity of the floor, and hence rigidity of the vehicle body, it is hard for the floor tunnel reinforcement to transmit an external load applied to the floor tunnel reinforcement to an upper body portion of the vehicle body upon an occurrence of a frontal collision or a rear-end collision. That is, the floor tunnel reinforcement is accompanied by a problem of a poor property of dispersing an external load.
On the other hand, as disclosed in, for example, Japanese Unexamined Patent Publication No. 11-78984, it has been proposed to improve the torsional rigidity of a vehicle body by installing a V-shaped reinforcement connected between a kick-up portion of a rear floor and an upper panel of a package compartment. However, there is no teaching regarding the property of dispersing an external load in the above mentioned publication.
It is therefore an object of the invention to provide a rear body structure for a vehicle body that realizes an improved property of dispersing an external load and high torsional rigidity of the vehicle body.
The foregoing object of the present invention is accomplished by a rear body structure comprising a floor tunnel extending in a lengthwise direction from the front to the back of the vehicle body at a middle of a floor pane! in a transverse direction of the vehicle body, a floor tunnel reinforcement disposed along the floor tunnel so as to form a closed cross section between them, a package member extending in the transverse direction so as to interconnect side walls between which a compartment is formed in the rear body, and a gusset, preferably a generally V-shaped gusset, secured to the floor tunnel reinforcement and the package member so as thereby to interconnect the floor tunnel reinforcement and the package member. According to the rear body, as the floor tunnel reinforcement, as a rigid structural member, and the package member are connected by the gusset, an external load applied to the floor tunnel reinforcement is transmitted to an upper body portion of the vehicle body through the gusset and the package member, so as to improve the property of dispersing an external load applied to the vehicle body In addition, the floor tunnel reinforcement improves the rigidity of both vehicle floor and vehicle body. Furthermore, the gusset provides an increase in the torsional rigidity of the vehicle body.
The rear body structure further comprises a bracket that is disposed between and secured to the floor tunnel reinforcement and the generally V-shaped gusset. The generally V-shaped gusset may be preferably shaped so as to form a closed cross section between the floor tunnel reinforcement. This structure improves fitting suitability and assembling workability of the generally V-shaped gusset.
The rear body structure further comprises a cross member forming a closed cross section extending in said transverse direction. This provides a double closed section structure at the joined section between the generally V-shaped gusset and the cross member, so as to improve rigidity of the joined section.
The generally V-shaped gusset preferably has a gusset reinforcement such as a bead, running the entire length thereof. This generally V-shaped gusset is enhanced in its own rigidity, so as to increase external load transmission efficiency and torsional rigidity of the vehicle body.
The comprises generally V-shaped gusset may comprise two mating gusset halves each of which preferably has a gusset reinforcement such as a bead running the entire length thereof.